← All parts of this equation

Equation 1 · Part 6 · How Systems and Computational Neuroscience Actually Work

fraction

ΔFF=F(t)−F0F0\frac{\Delta F}{F} = \frac{F(t) - F_0}{F_0}
fraction

What this part means

Divide the expression above the line by the one below it.

Its job in the formula

The expression above the fraction bar is divided by the complete expression below it. The denominator must not be zero.

The passage around this formula

Analysis. What the microscope actually outputs is a time series of fractional fluorescence change, conventionally reported as ΔFF=F(t)−F0F0\frac{\Delta F}{F} = \frac{F(t) - F_0}{F_0}. where F0F_0 is a baseline fluorescence estimated from a quiet period. Spikes are then inferred from this signal, not observed directly — calcium influx is slower than an action potential and low firing rates can fall below detection threshold, so a Δ\Delta F/F trace is a lossy, nonlinear encoding of spiking, not a direct spike train. Any claim about “single-spike resolution” from calcium imaging alone should be read skeptically unless the paper validates it against a simultaneous electrode recording.

Read this part in the article →

Learn the underlying idea

A fraction a/b means a divided by b. The top number is the numerator; the bottom number is the denominator, and it cannot be zero.

Open the illustrated fractions: division written vertically guide →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.